Nerfs in general don't feel good, but I think it's a matter of a degree... if players came up with 5 different skill sets that they didn't think of that were all pretty effective, awesome! But if one unexpected set rose to sheer dominance and made other skills or playstyles irrelevant, well, that's sort of removing choice from the players: "I want to play a character this way, but it seems like it'll never be as effective as this other way... damn it."
I for one think the glass cannon nerf was a bit extreme, but some other things like the wine barrel combo (telekinesis + strength + looting a wine barrel from the Cyseal barracks = 500 damage for 2 AP, starting from level 1 or 2) was obviously game-breaking. It made every single other playstyle irrelevant by comparison. (For what it's worth, the devs said they'll patch this for the EE; haven't actually checked to see if that's true)
